I broke up with my boyfriend, and lost other friends too.

My boyfriend and I were together for three years. Im 18. He's 19. We both had same group of friends until I broke up with him. I discovered that my bf was doing hard drug so I told him that it's not worth it. I was heartbroken. Somehow, the conversation got more tense. I ended up asking if he could promise me not to do it again. He replied that he couldn't keep promises. So I told him to make decision between drug or me. With all my caring, he chose drug. So I told him, I felt cheap. Drug beat me. I decided to walk out of his life because throughout three years, he broke my heart 4-5 times already. It reveals how little I meant for him. I was not his first partner, but he was my first love. After, I chose to end our relationship. Friends also left me and choose him for drug. They all made me feel like outsider and the wrong one. At one point, I had to apologize to the man who chose drug over me because I felt like I was the wrong one. Right now, I have one friend left. One friend who doesnt do hard drug. The thing is, that friend is my ex's brother. My ex was pissed at the brother for seeing me and told him not to hang out with me. He probably did the same thing to the other friends as well. I guess he wants me to suffer of loneliness by eliminating everyone I know. He succeeded. I am very lonely and vulnerable at the moment. Because I cared for his well-being, I lost everything in one day. Please help me.